U.S. patent application number 14/702909 was filed with the patent office on 2016-06-23 for capacitive sensing device and capacitive sensing method.
The applicant listed for this patent is IMAGINATION BROADWAY LTD., SALT INTERNATIONAL CORP.. Invention is credited to SHANG-LI LEE.
Application Number | 20160179246 14/702909 |
Document ID | / |
Family ID | 56129340 |
Filed Date | 2016-06-23 |
United States Patent
Application |
20160179246 |
Kind Code |
A1 |
LEE; SHANG-LI |
June 23, 2016 |
CAPACITIVE SENSING DEVICE AND CAPACITIVE SENSING METHOD
Abstract
A capacitive sensing method includes detecting present measured
values of plural reference points from plural sensing points;
generating a present difference value according to the present
measured values of the reference points and current reference
measured values; comparing the present difference value with a
threshold; detecting present measured values of the sensing points;
generating plural position signals of the sensing points according
to the present measured values of the sensing points and the
current reference measured values; and controlling the output of
the position signals according to a reference signal. When the
present difference value is greater than the threshold, executing a
procedure for refreshing background noise to refresh the current
reference measured values. The sensing points are defined by
intersected electrodes, configured to form an array, and correspond
to the current reference measured values. The reference points are
located at the periphery of the array.
Inventors: |
LEE; SHANG-LI; (New Taipei
City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SALT INTERNATIONAL CORP.
IMAGINATION BROADWAY LTD. |
New Taipei City
New Taipei City |
|
TW
TW |
|
|
Family ID: |
56129340 |
Appl. No.: |
14/702909 |
Filed: |
May 4, 2015 |
Current U.S.
Class: |
345/174 |
Current CPC
Class: |
G06F 3/0418 20130101;
G09G 2300/0426 20130101; G09G 5/003 20130101; G06F 3/044
20130101 |
International
Class: |
G06F 3/044 20060101
G06F003/044; G09G 5/00 20060101 G09G005/00; G06F 3/047 20060101
G06F003/047 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 19, 2014 |
TW |
103144610 |
Dec 19, 2014 |
TW |
103144611 |
Claims
1. A sensing method for a capacitive sensing device, comprising:
detecting present measured values of a plurality of reference
points selected from a plurality of sensing points, wherein the
sensing points are defined by electrodes intersected with one
another and the sensing point are configured to form an array,
wherein the sensing points correspond to a plurality of respective
reference measured values which is currently used, and wherein the
reference points are located at the periphery of the array;
generating a present difference value according to the present
measured values of the reference points and the reference measured
values which are currently used; comparing the present difference
value with a second threshold; executing a procedure for refreshing
background noise to refresh the reference measured values which are
currently used based on the present difference value when the
present difference value is greater than the second threshold;
detecting a plurality of present measured values of the sensing
points; generating a plurality of position signals of the sensing
points according to the present measured values of the sensing
points and the reference measured values which are currently used;
and controlling the output of the position signals according to a
reference signal.
2. The sensing method for a capacitive sensing device according to
claim 1, wherein the step of executing a procedure for refreshing
background noise to refresh the reference measured values which are
currently used with the present difference value when the present
difference value is greater than the second threshold comprises:
reading out a set of reference measured values corresponding to the
present difference value from a storage unit; and refreshing the
reference measured values which are currently used with the set of
read-out reference measured values.
3. The sensing method for a capacitive sensing device according to
claim 1, wherein the step of detecting present measured values of a
plurality of reference points selected from a plurality of sensing
points comprises: driving at least one electrode located at a first
side of the array and at least one electrode located at a second
side of the array from the electrodes, wherein the first side is
opposite to the second side; and measuring at least one electrode
located at a third side of the array and at least one electrode
located at a fourth side of the array from the electrodes to obtain
the present measured values of the reference points, wherein the
third side is opposite to the fourth side.
4. The sensing method for a capacitive sensing device according to
claim 1, wherein the step of detecting present measured values of a
plurality of reference points selected from a plurality of sensing
points comprises: driving and measuring at least one electrode
located at at least one side of the array from the electrodes to
obtain the present measured values of the reference points.
5. The sensing method for a capacitive sensing device according to
claim 1, wherein the electrodes comprise a plurality of first
electrodes and a plurality of second electrodes intersected with
the first electrodes, and wherein the step of detecting present
measured values of a plurality of reference points selected from a
plurality of sensing points further comprises: driving at least one
of the first electrodes located at a first side of the array and at
least one of the first electrodes located at a second side of the
array, wherein the first side is opposite to the second side; and
measuring a number of the second electrodes to obtain the present
measured values of the reference points.
6. The capacitive sensing method according to claim 5, wherein any
two of the measured second electrodes are spaced by at least one
unmeasured second electrode.
7. The capacitive sensing method according to claim 1, wherein the
electrodes comprise a plurality of first electrodes and a plurality
of second electrodes intersected with the first electrodes, and
wherein the step of detecting present measured values of a
plurality of reference points selected from a plurality of sensing
points further comprises: driving at least one of the first
electrodes located at a first side of the array and at least one of
the first electrodes located at a second side of the array, wherein
the first side is opposite to the second side; measuring at least
one of the second electrodes to obtain present measured values of
some of the reference points; driving at least one of the second
electrodes located at a third side of the array and a least one of
the second electrodes located at a fourth side, wherein the third
side is opposite to the fourth side; and measuring at least one of
the first electrodes to obtain present measured values of the rest
reference points.
8. The capacitive sensing method according to claim 7, wherein any
two of the measured first electrodes is spaced by at least one
unmeasured first electrode, and wherein any two of the measured
second electrodes is spaced by at least one unmeasured second
electrode.
9. The capacitive sensing method according to claim 1, wherein the
array is divided into a sensing area and an invalid area located at
the periphery of the sensing area, and the reference points are
located in the invalid area.
10. The capacitive sensing method according to claim 1, further
comprising: comparing the present difference value with a first
threshold; increasing a detecting frequency of the present measured
values of the reference points when the present difference value is
greater than the first threshold.
11. The capacitive sensing method according to claim 1, further
comprising: comparing the present difference value with a first
threshold; increasing a detecting frequency of the present measured
values of the reference points and reset a count value when the
present difference value is greater than the first threshold;
accumulating the count value when the present difference value is
not greater than the first threshold; decreasing the detecting
frequency of the present measured values of the reference points
and reset the count value when the count value is greater than or
equal to a predetermined value; and retaining the same detecting
frequency of the present measured values of the reference points
when the count value is not reached to the predetermined value.
12. A capacitive sensing device, comprising: a storage unit,
storing a reference signal and a plurality of sets of reference
measured values corresponding to respective present measured
values, wherein one set of reference measured values is set to be
used currently; a signal sensor, comprising a plurality of first
electrodes and a plurality of second electrodes, wherein the first
electrodes are intersected with the second electrodes, and the
first electrodes and the second electrodes define a plurality of
sensing points configured as an array, and wherein a plurality of
reference measured values selected from each set of reference
measured values corresponds to the respective sensing points; a
driving/sensing unit, connected to the first electrodes and the
second electrodes for detecting present measured values of the
sensing points; a position sensing unit, connected to the
driving/sensing unit and the storage unit for generating a present
difference value according to the reference measured values which
are currently used and present measured values of a plurality of
reference points selected from the sensing points, generating a
plurality of position signals according to the present measured
values of the sensing points and the set of reference measured
values which are currently used, and controlling the output of the
position signals according to the reference signal, wherein the
reference points are located at the periphery of the array; and a
control unit, connected to the storage unit, the driving/sensing
unit and the position sensing unit, for comparing the present
difference value with a second threshold, wherein the control unit
executes a procedure for refreshing background noise to refresh the
set of reference measured values which are currently used based on
the present difference value when the present difference value is
greater than the second threshold.
13. The capacitive sensing device according to claim 12, wherein in
the procedure for refreshing background noise, the control unit
reads out the set of reference measured values corresponding to the
present difference value from the storage unit and refreshes the
reference measured values which are currently used with the
read-out set of reference measured values.
14. The capacitive sensing device according to claim 12, wherein
the reference points are located at a corner of the array.
15. The capacitive sensing device according to claim 12, wherein
the array is divided into a sensing area and an invalid area
located at the periphery of the sensing area, and the reference
points are located in the invalid area.
16. The capacitive sensing device according to claim 12, wherein
the control unit adjusts a detecting frequency of the
driving/sensing unit applied to the present measured values of the
reference points according to the present difference value and a
first threshold.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This non-provisional application claims priority under 35
U.S.C. .sctn.119(a) on Patent Application No. 103144611 and
103144610, filed in Taiwan, R.O.C. on Dec. 19, 2014, the entire
contents of which are hereby incorporated by reference.
[0002] This application is related to U.S. Application Serial No.
_____ (Docket: P144154US), entitled "CAPACITIVE SENSING DEVICE AND
CAPACITIVE SENSING METHOD", with an inventor LEE, SHANG-LI, that is
being filed on the same day as the present application.
BACKGROUND
[0003] 1. Technical Field
[0004] The instant disclosure relates to capacitive sensing
technologies, in particular, to a capacitive sensing device and
method thereof capable of reducing the influence from transient
environmental changes.
[0005] 2. Related Art
[0006] For the sake of improving convenience of usage, more and
more electronic devices adopt touch screens as operating
interfaces. A user can touch graphics displayed on a touch screen
of an electronic device for manipulating the electronic device.
Comparing to button-based manipulations or other manipulation
methods, touch-based manipulations are quicker, more convenient,
and more ergonomic. The touch screen mainly includes a display
device providing a displaying function and a sensing device
providing a touching function.
[0007] These sensing devices can be classified, according to the
structures and the principles applied, into several sensing types,
such as resistive sensing, capacitive sensing, acoustic sensing,
optic sensing (e.g., infrared ray sensing), and electromagnetic
sensing. Specifically, the capacitive sensing devices (i.e.,
sensing devices belonging to capacitive sensing type) do not
require materials having good properties in terms of stress and
strain, and are not easily affected by environment light.
Furthermore, the manufacturing process of the capacitive sensing
devices is simpler than other types of sensing devices. Therefore,
most of touch screens which are recently manufactured intend to
adopt the capacitive sensing device for the touch-based
manipulation.
[0008] A conventional capacitive sensing device includes sensing
points which are defined by X electrodes and Y electrodes and are
configured in an array form. When the user touches the conventional
capacitive sensing device, a capacitance value of at least a
corresponding sensing point on which the user touches would be
changed, and then the conventional capacitive sensing device
identifies that a touch manipulation occurs by detecting a
variation of the capacitance value of the sensing point. However,
when the environment of the conventional capacitive sensing device
transiently changes (e.g., temperature change in a short period of
time), the capacitive value of the sensing point would increase or
decrease according to the environment temperature, such that the
conventional capacitive sensing device would misjudge the change of
the capacitive value of the sensing point as a touch
manipulation.
SUMMARY
[0009] Therefore, the instant disclosure provides a capacitive
sensing method and a device therefor to more correctly sense the
touch manipulation.
[0010] In one embodiment, a capacitive sensing method is provided
and comprises steps of: detecting present measured values of a
plurality of reference points selected from a plurality of sensing
points; generating a present difference value according to the
present measured values of the reference points and reference
measured values which are currently used; comparing the present
difference value with a threshold; detecting present measured
values of the sensing points; generating a plurality of position
signals of the sensing points according to the present measured
values of the sensing points and the reference measured values
which are currently used; and controlling the output of the
position signals according to a reference signal. Wherein,
executing a procedure for refreshing background noise to refresh
the reference measured values which are currently used based on the
present difference value when the present difference value is
greater than the threshold. Wherein, the sensing points are defined
by electrodes intersected with one another, and the sensing points
are configured to form an array. Wherein, the reference points are
located at the periphery of the array. Wherein, the sensing points
correspond to the reference measured values which are currently
used.
[0011] In one embodiment, a capacitive sensing device is provided
and comprises a storage unit, a signal sensor, a driving/sensing
unit, a position sensing unit, and a control unit. The storage unit
stores a reference signal and a plurality of sets of reference
measured values corresponding to respective present measured
values, and one set of the reference measured values is set to be
used currently. The signal sensor comprises a plurality of first
electrodes and a plurality of second electrodes. The first
electrodes are intersected with the second electrodes, the first
electrodes and the second electrodes define a plurality of sensing
points configured as an array, and a plurality of reference
measured values selected from each set of reference measured values
corresponds to the respective sensing points. The driving/sensing
unit is connected to the first electrodes and the second electrodes
for detecting present measured values of the sensing points. The
position sensing unit is connected to the driving/sensing unit and
the storage unit for generating a present difference value
according to the reference measured values which are currently used
and present measured values of a plurality of reference points
selected from the sensing points, generating a plurality of
position signals according to the present measured values of the
sensing points and the set of reference measured values which are
currently used, and controlling the output of the position signals
according to the reference signal. Wherein, the reference points
are located at the periphery of the array. Wherein, the control
unit is connected to the storage unit, the driving/sensing unit,
and the position sensing unit, for comparing the present difference
value with a threshold. Wherein, when the present difference value
is greater than the threshold, the control unit executes a
procedure for refreshing background noise to refresh the set of the
reference measured values which are currently used based on the
present difference value.
[0012] According to the capacitive sensing device and the
capacitive sensing method of the instant disclosure, the device
detects the signals of the selected reference points in cycles.
Based on the detection result, the default background noises (i.e.,
the reference measured values), and the relation settings for
indicating the effect of temperature change to the position
signals, the device can obtain the impact of temperature change on
the position signals rapidly and adjust the position signals
correspondingly. Therefore, the accuracy of a signal-reading
process can be maintained over time and the response speed for
temperature change can be improved.
[0013] Detailed description of the characteristics and the
advantages of the disclosure is shown in the following embodiments,
the technical content and the implementation of the disclosure
should be readily apparent to any person skilled in the art from
the detailed description, and the purposes and the advantages of
the disclosure should be readily understood by any person skilled
in the art with reference to content, claims and drawings in the
disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 illustrates a schematic block diagram of a capacitive
sensing device according to an embodiment of the instant
disclosure;
[0015] FIG. 2 illustrates a top view of a signal sensor;
[0016] FIG. 3 illustrates a flowchart of an embodiment of a
capacitive sensing method according to the instant disclosure;
[0017] FIG. 4 illustrates a flowchart of another embodiment of a
capacitive sensing method according to the instant disclosure;
[0018] FIG. 5 is a flowchart illustrating a method for establishing
relation settings in an embodiment of the capacitive sensing method
according to the instant disclosure;
[0019] FIG. 6 is a flowchart illustrating a method for measuring
values of reference points of an embodiment of the capacitive
sensing method according to the instant disclosure;
[0020] FIG. 7 is a flowchart illustrating a method for measuring
values of reference points of another embodiment of the capacitive
sensing method according to the instant disclosure;
[0021] FIG. 8 is a flowchart illustrating a method for measuring
values of reference points of yet another embodiment of the
capacitive sensing method according to the instant disclosure;
[0022] FIG. 9 is a flowchart of yet another embodiment of a
capacitive sensing method according to the instant disclosure;
and
[0023] FIG. 10 is a flowchart showing details of the step S95.
DETAILED DESCRIPTION
[0024] Please refer to FIG. 1, illustrating a schematic block
diagram of a capacitive sensing device according to an embodiment
of the instant disclosure. As shown in FIG. 1, a touch screen
comprises a capacitive sensing device, a display device 20, and a
mainframe 30. The capacitive sensing device comprises a controller
12 and a signal sensor 14. The signal sensor 14 is connected to the
controller 12, and the signal sensor 14 is disposed on a displaying
surface of the display device 20. The signal sensor 14 comprises a
number of electrodes (e.g., a plurality of first electrodes X1,
X2-Xn-1, Xn and a plurality of second electrodes Y1, Y2-Ym-1, Ym)
intersected with one another (the first electrodes are intersected
with the respective second electrodes). Wherein, n and m are
positive integers and n may be equal to or not equal to m.
[0025] In some embodiments, the first electrodes X1, X2-Xn-1, Xn
and the second electrodes Y1, Y2-Ym-1, Ym may be respectively
disposed on different planes. In other words, the signal sensor 14
comprises a first sensing layer 142 and a second sensing layer 144.
The second sensing layer 144 is disposed above the first sensing
layer 142, and the first sensing layer 142 is disposed on the
displaying surface of the display device 20. An insulating layer
may be, but not limited to, disposed between the first sensing
layer 142 and the second sensing layer 144.
[0026] The first sensing layer 142 comprises a number of electrodes
(i.e., the first electrodes X1, X2-Xn-1, Xn) configured in a
pattern form. The first electrodes X1, X2-Xn-1, Xn are parallel
with one another. Likewise, the second sensing layer 144 comprises
a number of electrodes (i.e., the second electrodes Y1, Y2-Ym-1,
Ym) configured in a pattern form. As shown in FIG. 2, the first
electrodes X1, X2-Xn-1, Xn are intersected with the second
electrodes Y1, Y2-Ym-1, Ym to define a plurality of sensing points
P(1,1)-P(n,m) configured as an array. That is, the first electrodes
X1, X2-Xn-1, Xn and the second electrodes Y1, Y2-Ym-1, Ym
corporately form a plane coordinate system. In this embodiment, the
first electrodes X1, X2-Xn-1, Xn and the second electrodes Y1,
Y2-Ym-1, Ym corporately form, but are not limited to, a Cartesian
coordinate system. In other embodiments, the plane coordinate
system may be a polar coordinate system, non-rectangular coordinate
system, or other kinds of plane coordinate systems. In some
embodiments, a top view of the intersected first electrodes X1,
X2-Xn-1, Xn and second electrodes Y1, Y2-Ym-1, Ym may show a
repeated rhombus pattern, a grid pattern, or a railing pattern.
[0027] In addition, the first electrodes X1, X2-Xn-1, Xn and the
second electrodes Y1, Y2-Ym-1, Ym may be disposed on the same
plane. That is, the first electrodes X1, X2-Xn-1, Xn and the second
electrodes Y1, Y2-Ym-1, Ym are disposed on a single sensing
layer.
[0028] Sensing layers (e.g., the first sensing layer 142 and the
second sensing layer 144) may be transparent or translucent.
Therefore, by seeing through all of the sensing layers, contents
displayed on the displaying surface by the display device 20 are
visible to a user. In other words, light rays emitted from the
display device 20 can penetrate and pass through all of the sensing
layers to reach the eyes of the user. In some embodiments, the
sensing layers may be patterned electric conductive thin films,
such as but not limited to, indium tin oxide (ITO) films.
[0029] An area of the display device 20 utilized for displaying
contents is generally called an active area. An area on which the
signal sensor 14 overlaps the active area is called a sensing area
A1. Any touch events occurred on the sensing area A1 can be
detected by the signal sensor 14. The term "touch event" means a
physical touch (i.e., at least one finger or at least one object
directly touches the signal sensor 14) or a near touch (i.e., at
least one finger or at least one object extremely closes to but do
not directly touches the signal sensor 14). In some embodiments,
all of the sensing points P(1, 1)-P(n, m) of the signal sensor 14
are located in the active area, meaning that the signal sensor 14
is devoid of invalid areas A2. In some embodiments, part of the
sensing points P(1, 1)-P(1, m) and P(n, 1)-P(n, m) of the signal
sensor 14 are not located in the active area, meaning that the
signal sensor 14 comprises an invalid area A2 located at the
periphery of the sensing area A1. Any touch event occurred on the
invalid area A2 cannot be detected by the signal sensor 14.
[0030] During the operation of the touch screen, the mainframe 30
transmits contents to be displayed to the display device 20 of the
touch screen, and the display device 20 displays a graphics having
the contents to be displayed. When the user touches a specific
position of the capacitive sensing device on which the display
device 20 overlaps according to the graphics displayed by the
display device 20, the capacitive sensing device responds to the
touch event and then transmits a position signal corresponding to
the specific position to the mainframe 30 for a further processing.
Here, what the further processing does depends on an executing
command corresponding to the touched specific position to which an
area of the graphics of the display device 20 corresponds. For
example, the mainframe 30 may, but not limited to, respond to the
position signal to execute a certain application or to display a
brush stroke on the area of the display device 20 corresponding to
the touched specific position. In other words, the mainframe 30 can
receive the position signal from the capacitive sensing device and
can be configured to initiate a certain operation based on the
position signal.
[0031] Next, the controller 12 comprises a driving/sensing unit
122, a position sensing unit 124, a storage unit 126, and a control
unit 128. The driving/sensing unit 122 comprises a driving
component and a sensing component. Depending on different
situations, the driving component may be integrated with the
sensing component, or the driving component may be separated from
the sensing component and electrically connected to the sensing
component. The driving/sensing unit 122 is electrically connected
to the first electrodes X1, X2-Xn-1, Xn and the second electrodes
Y1, Y2-Ym-1, Ym. The position sensing unit 124 is electrically
connected to the driving/sensing unit 122, the storage unit 126,
and the main frame 30. The control unit 128 is electrically
connected to the driving/sensing unit 122, the position sensing
unit 124, and the storage unit 126. Here, the control unit 128 is
utilized for controlling the driving/sensing unit 122.
[0032] When the controller 12 detects any touch event triggered by
a user, the driving/sensing unit 122 detects a measured value of
each of the sensing points by capacitive sensing technologies like
self-capacitance detection or mutual capacitance detection. Here,
the measured values may be voltages, currents, the charge/discharge
times, or other parameters of the sensing points. In other words, a
present measured value of each of the sensing points is detected by
the driving/sensing unit 122, and a capacitance value or a change
of capacitive value of each of the sensing points (i.e., the
position signal) is obtained according to the detected present
measured value and the corresponding reference measured value of
each of the sensing points by the position sensing unit 124.
[0033] Here, the sensing points located at a designated position
are selected to be reference points. Preferably, the selected
sensing points (i.e., the reference points) may be in the invalid
area A2, or the selected sensing points may be in the sensing area
A1 but has less chance in occurrence of the touch event. Namely,
those sensing points in the periphery of the array of the sensing
points P(1,1)-P(n,m) are selected to be the reference points.
[0034] During a normal working cycle, the control unit 128 controls
the driving/sensing unit 122 to detect signals of the reference
points by a certain detecting frequency. Here, the certain
detecting frequency may be, but not limited to, 2-5 seconds per
scan.
[0035] Referring to the step S11 of FIG. 3, the control unit 128
controls the driving/sensing unit 122 to detect present measured
values of the reference points.
[0036] Referring to the step S13 of FIG. 3, the position sensing
unit 124 generates a present difference value according to the
present measured values of the reference points and at least one
reference measured value. Next, referring to the step S15 of FIG.
3, the position sensing unit 124 obtains a selected adjustment
factor according to a relation setting and the present difference
value. Here, the relation setting is the relationship between
adjustment factors and signal difference values corresponding to
different temperatures.
[0037] And, referring to the step S17 of FIG. 3, the control unit
128 controls the driving/sensing unit 122 to detect present
measured values of all the sensing points located in the sensing
area A1. Then, referring to the step S19 of FIG. 3, the position
sensing unit 124 generates a plurality of position signals of the
sensing points located in the sensing area A1 according to the
present measured values of the sensing points located in the
sensing area A1. That is, the driving/sensing unit 122 calculates
the present difference value (i.e., the capacitance value or the
change of capacitive value) of each of the sensing points as the
position signal of each of the sensing points according to the
present measured value of each of the sensing points and the
corresponding reference measured value. Next, referring to the step
S21 of FIG. 3, the position sensing unit 124 adjusts the position
signals according to the selected adjustment factor. Then, the
position sensing unit 124 controls the output of the adjusted
position signals according to a reference signal.
[0038] In some embodiments, referring to the step S31 of FIG. 4,
every time the present difference value is obtained (namely, after
the step S13), the control unit 128 compares the present difference
value with a threshold (hereinafter, called first threshold; the
first threshold may be, but not limited to, called frequency
adjusting threshold). Referring to the step S33 and the step S35 of
FIG. 4, when the present difference value is greater than the first
threshold, the control unit 128 increases the frequency of the
signals of the reference points by the driving/sensing unit 122 to
detect.
[0039] In some embodiments, when the present difference value is
not greater than the first threshold, the control unit 128 controls
a counter to add a count value by 1 (step S37), and then determines
whether the count value is reached (i.e., substantially equal to or
greater than) to a predetermined value or not (step S37). When the
count value is reached to the predetermined value, the control unit
128 decreases the frequency of the signals of the reference points
by the driving/sensing unit 122 to detect (step S41).
[0040] In addition, when the detecting frequency is confirmed to be
adjusted or when the detecting frequency is adjusted (step S41 or
Step S35), the control unit 128 resets the counter to zero the
count value (Step S43).
[0041] Otherwise, when the count value is not reached to the
predetermined value, the control unit 128 maintains the same
detecting frequency (Step S45).
[0042] In some embodiments, the relation settings may be
established by the following method.
[0043] Referring to the step S51 of FIG. 5, a number (e.g., ten,
twenty, thirty, or more) of capacitive sensing devices with the
same specification (e.g., the same size and the same thickness of
glass) and the same manufacturing time are chosen.
[0044] Referring to the step S53 of FIG. 5, place the capacitive
sensing devices with the same specification in a
temperature-controlling environment. Specifically, control the
temperature of the environment at around a first temperature. The
first temperature may be an ambient temperature, for instance, but
not limited to, 26 degree Celsius, 27 degree Celsius, or 28 degree
Celsius. Then, the same sensing technology is performed to measure,
by one time or by many times, the measured value (or values) of the
same reference point of each of the capacitive sensing devices in
condition of no actual touch event (called first measured value (or
values)), and to measure the position signal of each of the sensing
points (called first position signal).
[0045] Referring to the step S55 of FIG. 5, then, the reference
measured value is calculated according to the first measured values
in a statistics manner.
[0046] In one embodiment, the reference measured value may be the
mean value of the first measured value obtained at the same
reference point of different devices (that is, the position of a
first reference point of a first capacitive sensing device
corresponds to the position of a first reference point of a second
capacitive sensing device, and so on). Besides, before obtaining
the mean value of the first measured values, the outliers of the
first measured values may be deleted in advance. Next, in the step
S13, the present difference value is the statistical values of
individual difference values. Each of individual difference values
is the difference between the present measured value of each of the
reference points and each corresponding reference measured value at
the same reference point. The statistical value may be, but not
limited to, mean, median, or mode.
[0047] In another embodiment, the reference measured value may be
the mean value of the first measured values obtained at all
reference points of different devices. Accordingly, the reference
measured value corresponds to all the reference points of different
devices. Besides, before obtaining the mean value of the first
measured values, the outliers of the first measured values may be
deleted in advance. Next, in the step S13, the present difference
value is the statistical values of individual difference values.
Each of individual difference values is the difference between the
present measured value of each of the reference points and the same
reference measured value. The statistical value may be, but not
limited to, mean, median, or mode.
[0048] In yet another embodiment, the reference measured value may
be the mean value of the first measured values obtained at all the
reference points of at least one electrode located at the same
position of different devices. Accordingly, the reference measured
value corresponds to all the reference points of different devices.
Besides, before obtaining the mean value of the first measured
values, the outliers of the first measured values may be deleted in
advance. Next, in the step S13, the present difference value is the
statistical values of individual difference values. Each of
individual difference values is the difference between the present
measured value of each of the reference points and the
corresponding reference measured value at the same reference point.
The statistical value may be, but not limited to, mean, median, or
mode.
[0049] Wherein, a method of deleting the first measured values
having greater deviations may be, but not limited to, deleting the
one having the greatest value, deleting the one having the least
value, deleting the ones respectively having the greatest value and
the least value, or deleting the outliers of the first measured
values.
[0050] Referring to the step S57 of FIG. 5, place the capacitive
sensing devices with the same specification in a
temperature-controlling environment. Specifically, control the
temperature of the environment at around a number of second
temperatures higher than or lower than the first temperature. Then,
the same sensing technology is performed to measure, by same times,
the measured value (or values) of the same reference point of each
of the capacitive sensing devices in the condition of no actual
touch event (called second measured value (or values)), and to
measure the position signal of each of the sensing points (called
second position signal).
[0051] Referring to the step S59 of FIG. 5, utilizing the
measurement result (i.e., the first measured values and the
corresponding first position signals at around the first
temperature, and the second measured values and the corresponding
second position signals at around the second temperatures) to
perform statistics analysis to obtain the relation setting, the
relationship between signal difference values (representing the
temperature change between the first temperature and the second
temperatures), and adjustment factors (representing the signal
change between the first position signals and the second position
signals). Here, the relation setting may be a lookup table between
the signal difference values and the adjustment factors, a curve
plotted by the signal difference value and the adjustment factors,
or an equation relating to the signal difference values and the
adjustment factors. In one embodiment of the step S15, the position
sensing unit 124 figures out the signal difference value matching
with the present difference value in the relation setting, and
then, the position sensing unit 124 further obtains the adjustment
factor corresponding to the signal difference value matching with
the present difference value (i.e., the selected adjustment
factor). In another embodiment of the step S15, the position
sensing unit 124 substitutes the present difference value into the
relation setting to obtain the corresponding adjustment factor
(namely, the selected adjustment factor).
[0052] For a temperature range defined by a first temperature and a
second temperature in Celsius, the temperature scale is at least
one degree per indicium (e.g., 1 C, 2 C, 5 C, 10 C). When the
magnitude of the indicium is rather less, the signal difference
values corresponding to different temperatures may be the same.
Besides, different signal difference values may correspond to
adjustment factors having the same value.
[0053] Next, referring to the step S61 of FIG. 5, the reference
measured value and the corresponding relation setting are stored in
the storage units of the capacitive sensing devices with the same
specification for the further use in the step S13 and the step
S15.
[0054] In some embodiments, the reference points may be defined at
a k number of electrodes (X1-Xk, Xn-k-1-Xn, Y1-Yk, Ym-k-1-Ym,
hereinafter called reference electrodes) located at the periphery
of the array. Wherein, k is a positive integer and is less than n
or less than m. Preferably, k is a positive integer and is less
than n/10 or less than m/10. More preferably, k is 1 or 2. Here,
the reference points may be one sensing point, a number of sensing
points or all the sensing points of each of the reference
electrodes.
[0055] In addition, for each of the reference electrodes, any two
adjacent reference points are spaced by one or more sensing points
which are not the reference points. Moreover, for each of the
reference electrodes, the number of the spaced sensing points
between any two adjacent reference points is the same.
[0056] In some embodiments, the reference points are sensing points
at corners of the array. That is, the reference points are a a*b
number of sensing points located at the corners of the array. Here,
a is a positive integer and is less than n. Preferably, a is a
positive integer and is less than n/10. More preferably, a is 1 or
2. Moreover, b is a positive integer and is less than m.
Preferably, b is a positive integer and is less than m/10. More
preferably, b is 1 or 2.
[0057] In some embodiments, the reference points are the sensing
points located in the invalid area A2. For example, one or more of
the sensing points (P(1,1)-P(1,m), P(n,1)-P(n,m)) may be the
reference points.
[0058] In some embodiments, the touch screen is assembled to an
apparatus (e.g., the mainframe 30) to compose a single integrated
electronic device. In the situation, the selection of the reference
point prefers to avoid a heat source of the apparatus. In other
words, selecting sensing points which are not in an area near or
above the heat source of the apparatus to be the reference points
is preferable.
[0059] Here, the reference points utilized in the measuring step
for measuring the first measured values in the step S11 and the
step S53 are the same as the reference points utilized in the
measuring step for measuring the second measured values in the step
S57.
[0060] Details about the measuring step for measuring the first
measured values in the step S11 and the step S53 and the measuring
step for measuring the second measured values in the step S57 are
further described. Referring to FIG. 1, FIG. 2, and FIG. 6, in a
first embodiment of the measuring step for measuring the first
measured values in the step S11 and the step S53 and the measuring
step for measuring the second measured values in the step S57, the
reference points are a 2*1 number of sensing points located at each
corner of the array (for example, P(1,1) and P(2,1), P(1,m) and
P(2,m), P(n,1) and P(n-1,1), and P(n,m) and P(n-1,m)), and the
driving/sensing unit 122 drives two first electrodes X1, X2 located
at a first side of the array and two first electrodes Xn-1, Xn
located at a second side of the array (step S71). Wherein, the
first side is opposite to the second side.
[0061] Next, the driving/sensing unit 122 measures one second
electrode Y1 located at a third side of the array and one second
electrode Yn located at a fourth side of the array to obtain the
present measured values of the reference points (step S73).
Wherein, the third side is opposite to the fourth side. The third
side is connected between one of two ends of the first side and one
of two ends of the second side, and the fourth side is connected
between the other end of the first side and the other end of the
second side.
[0062] In other words, as shown in FIG. 2, the driving/sensing unit
122 drives the leftmost two first electrodes X1, X2 and the
rightmost two first electrodes Xn, Xn-1 of the signal sensor 14.
And then, the driving/sensing unit 122 measures the topmost one
second electrode Ym and the bottommost one second electrode Y1 of
the signal sensor 14.
[0063] In a second embodiment of the measuring step for measuring
the first measured values in the step S11 and the step S53 and the
measuring step for measuring the second measured values in the step
S57, the reference points are one sensing point located at each
corner of the array (for example, P(1,1), P(1,m), P(n,1), and
P(n,m)), and the driving/sensing unit 122 drives one first
electrode X1 located at the first side of the array (i.e., the
leftmost first electrode) and one first electrode Xn located at the
second side of the array (i.e., the rightmost first electrode)
(step S71). Next, the driving/sensing unit 122 measures one second
electrode Ym located at the third side of the array (i.e., the
topmost second electrode) and one second electrode Y1 located at
the fourth side of the array (i.e., the bottommost second
electrode) to obtain the present measured values of the reference
points (step S73).
[0064] In a third embodiment of the measuring step for measuring
the first measured values in the step S11 and the step S53 and the
measuring step for measuring the second measured values in the step
S57, the reference points are a 1*2 number of sensing points
located at each corner of the array (for example, P(1,1) and
P(1,2), P(1,m) and P(1,m-1), P(n,1) and P(n,2), and P(n,m-1) and
P(n,m)), and the driving/sensing unit 122 drives one first
electrode X1 located at the first side of the array and one first
electrode Xn located at the second side of the array (step S71).
Next, the driving/sensing unit 122 measures two second electrodes
Ym, Ym-1 located at the third side of the array and two second
electrodes Y1, Y2 located at the fourth side of the array to obtain
the present measured values of the reference points (step S73).
[0065] Referring to FIG. 1, FIG. 2, and FIG. 7, in a fourth
embodiment of the measuring step for measuring the first measured
values in the step S11 and the step S53 and the measuring step for
measuring the second measured values in the step S57, the reference
points are the sensing points located at one electrode of the first
side of the array, and the driving/sensing unit 122 adopts the
self-capacitance detection. The driving/sensing unit 122 drives one
first electrode X1 located at the first side of the array (step
S75) and measures the first electrode X1 to obtain present measured
values of a number of reference points (i.e., the sensing points
P(1,1)-P(1,m))(step S77). In this embodiment, the reference points
(i.e., the sensing points P(1,1)-P(1,m)) are located in the invalid
area A2.
[0066] In a fifth embodiment of the measuring step for measuring
the first measured values in the step S11 and the step S53 and the
measuring step for measuring the second measured values in the step
S57, the reference points are the sensing points located at two
electrodes of the first side of the array, and the driving/sensing
unit 122 adopts the self-capacitance detection. The driving/sensing
unit 122 drives the two first electrode X1, X2 located at the first
side of the array (step S75) and measures the two first electrodes
X1, X2 to obtain present measured values of a number of reference
points (i.e., the sensing points P(1,1)-P(1,m) and
P(2,1)-P(2,m))(step S77).
[0067] In a sixth embodiment of the measuring step for measuring
the first measured values in the step S11 and the step S53 and the
measuring step for measuring the second measured values in the step
S57, the reference points are the sensing points located at one
electrode of each of the sides of the array, and the
driving/sensing unit 122 adopts the self-capacitance detection. The
driving/sensing unit 122 drives and measures one first electrode X1
located at the first side of the array to obtain present measured
values of a number of reference points (i.e., the sensing points
P(1,1)-P(1,m)). Next, the driving/sensing unit 122 drives and
measures one first electrode Xn located at the second side of the
array to obtain present measured values of a number of reference
points (i.e., the sensing points P(n,1)-P(n,m)). Then, the
driving/sensing unit 122 drives and measures one second electrode
Ym located at the third side of the array to obtain present
measured values of a number of reference points (i.e., the sensing
points P(1,m)-P(n,m)). And, the driving/sensing unit 122 drives and
measures one second electrode Y1 located at the fourth side of the
array to obtain present measured values of a number of reference
points (i.e., the sensing points P(1,1)-P(n,1)). In this
embodiment, some of the reference points (i.e., sensing points
P(1,1)-P(1,m) and P(n,1)-P(n,m)) are located in the invalid area
A2.
[0068] Referring to FIG. 1, FIG. 2, and FIG. 8, in a seventh
embodiment of the measuring step for measuring the first measured
values in the step S11 and the step S53 and the measuring step for
measuring the second measured values in the step S57, the reference
points are an i number of sensing points located at one first
electrode X1 of the first side of the array, and the
driving/sensing unit 122 adopts the self-capacitance detection.
Wherein, i is a positive integer between 1 to m. Preferably, i is
less than m. More preferably, i is less than m/2. The
driving/sensing unit 122 drives the first electrode X1 located at
the first side of the array (step S79). And then, the
driving/sensing unit 122 measures a i number of second electrodes
to obtain present measured values of a number of reference points
(step S81). Here, each two measured second electrodes are spaced by
one or more unmeasured second electrodes. In addition, any two
adjacent measured second electrodes may be spaced by a constant
number of unmeasured second electrodes. Alternatively, any two
adjacent measured second electrodes may be spaced by a different
number of unmeasured second electrodes. For example, if the number
of the second electrodes is sixteen, the first, fifth, ninth, and
thirteenth second electrodes Y1, Y5, Y9, Y13 are measured in the
step S77 to obtain present measured values of a number of reference
points (i.e., sensing points P(1,1), P(1,5), P(1,9), and P(1,13)).
Here, one first electrode is driven, but embodiments are not
limited thereto. Optionally, the driving/sensing unit 122 may drive
a number of first electrodes located at the same side of the array
or drive a number of first electrodes each located at different
sides of the array.
[0069] In an eighth embodiment of the measuring step for measuring
the first measured values in the step S11 and the step S53 and the
measuring step for measuring the second measured values in the step
S57, the driving/sensing unit 122 further drives one first
electrode located at the second side of the array (step S79), and
measures an i number of second electrodes to obtain present
measured values of a number of reference points (step S81). Similar
to the foregoing embodiment, if the number of the second electrodes
is sixteen, the driving/sensing unit 122 would obtain present
measured values of a number of reference points (i.e., sensing
points P(1,1), P(1,5), P(1,9), P(1,13), P(n,1), P(n,5), P(n,9), and
P(n,13)).
[0070] In a ninth embodiment of the measuring step for measuring
the first measured values in the step S11 and the step S53 and the
measuring step for measuring the second measured values in the step
S57, the driving/sensing unit 122 firstly obtains present measured
values of parts of reference points in the step S81. And then, the
driving/sensing unit 122 drives one second electrode Ym located at
the third side of the array (step S83), and measures a j number of
first electrodes to obtain present measured values of rest of the
reference points (step S85). Here, j is a positive integer between
1 to n. Preferably, j is less than n. More preferably, j is less
than n/2. In addition, each two measured first electrodes are
spaced by one or more unmeasured first electrodes. Further, any two
adjacent measured first electrodes may be spaced by a constant
number of unmeasured second electrodes. Alternatively, any two
adjacent measured second electrodes may be spaced by a different
number of unmeasured first electrodes. Similar to the foregoing
embodiment, if the number of the first electrodes is sixteen, in
the step S85, the driving/sensing unit 122 would measure, in an
arithmetic manner, the first, fifth, ninth, and thirteenth
electrodes X1, X5, X9, X13 to obtain present measured values of a
number of reference points (i.e., sensing points P(1,1), P(5,1),
P(9,1), and P(13,1)). Here, one second electrode is driven, but
embodiments are not limited thereto. Optionally, the
driving/sensing unit 122 may drive a number of second electrodes
located at the same side of the array or drive a number of second
electrodes each located at different sides (i.e., the third side
and the fourth side) of the array.
[0071] In a tenth embodiment of the measuring step for measuring
the first measured values in the step S11 and the step S53 and the
measuring step for measuring the second measured values in the step
S57, all the reference points are located in the invalid area A2.
Therefore, the driving/sensing unit 122 drives and/ or measures the
first electrodes X1, Xn. While in the step S17, the driving/sensing
unit 122 does not drive and/ or measures the first electrodes X1,
Xn.
[0072] Here, the driving/sensing unit 122 sequentially drives the
electrodes and sequentially then measures the electrodes.
Alternatively, in a multiprocessing manner, the driving/sensing
unit 122 may simultaneously drive a number of electrodes which are
aligned along the same direction, and the driving/sensing unit may
simultaneously measure a number of electrodes which are aligned
along the same direction.
[0073] In some embodiments, the storage unit 126 stores a plurality
of sets of reference measured values and relation settings
corresponding thereto. Here, each set of reference measured values
correspond to a temperature (i.e., correspond to one or more signal
difference values). In other words, the sets of reference measured
values correspond to different temperatures.
[0074] Please refer to FIG. 9, every time after the present
difference value is obtained (i.e., after the step S13), the
control unit 128 would then compare the present difference value
with another threshold (hereinafter called second threshold; the
second threshold may be, but not limited to, called background
noise refreshing threshold) (step S91). When the present difference
value is greater than the second threshold (step S93), the control
unit 128 executes a procedure for refreshing background noise
(hereinafter, called refreshing procedure) (step S95) so as to
replace the reference measured value which is currently used with a
set of reference measured values which is more dependent upon
current environment (e.g., environment temperature) and with the
relation settings. Next, the step S17, step S19 and step S23 are
executed sequentially (without the execution of the step S21).
Based on the step S93, when the present difference value is not
greater than the second threshold, the step S15 is executed.
[0075] In one embodiment of the step S95, as shown in FIG. 10, the
control unit 128 reads out a set of reference measured values
corresponding to the present difference value and relation settings
corresponding to the set of reference measured values from the
storage unit 126 (step S951). Next, in the step 5953, the control
unit 128 refreshes the reference measured values which are
currently used with the set of read-out reference measured values
for further use in the step S13 (and the step S19). Further, in the
step S953, the control unit 128 further replaces the relation
settings which are currently used with the read-out relation
settings for further use in the step S15.
[0076] In some embodiments, the signal detection of reference
points can be used in determining the timing to refresh the
background noises (i.e., the reference measured values). In other
words, when the present difference value is not greater than the
second threshold (step S93), instead of executing the step S15, the
step S17 is executed. In the step 5951, the set of read-out
reference measured values corresponds to respective sensing points
P(1,1)-P(n,m). Wherein, a set of reference measured values
corresponding to respective present difference values can be
established in advance and stored in the storage unit 126. That is,
the storage unit 126 stores a plurality of sets of reference
measured values corresponding to respective present difference
values, and each set of reference measured values corresponds to
respective sensing points P(1,1)-P(n,m). One of the sets of
reference measured values is set to be used currently for executing
the step S13 and the step S19.
[0077] It shall be understood that the order for executing the
described steps can be varied according to different situations.
Here, the storage unit 126 can be carried out by a single or a
multiple storage element. The storage element can be utilized for
storing or temporally storing software, firmware, information,
signals, values, documents, or the combination thereof. And, the
storage element may be, but not limited to, a volatile memory or a
non-volatile memory.
[0078] According to the capacitive sensing device and the
capacitive sensing method of the instant disclosure, the device
detects the signals of the selected reference points in cycles.
Based on the detection result, the default background noises (i.e.,
the reference measured value s), and the relation settings for
indicating the effect of temperature change to the position
signals, the device can obtain the impact of temperature change on
the position signals rapidly and adjust the position signals
correspondingly. Therefore, the accuracy of a signal-reading
process can be maintained over time and the response speed for
temperature change can be improved.
[0079] While the instant disclosure has been described by way of
example and in terms of the preferred embodiments, it is to be
understood that the invention needs not be limited to the disclosed
embodiments. For anyone skilled in the art, various modifications
and improvements within the spirit of the instant disclosure are
covered under the scope of the instant disclosure. The covered
scope of the instant disclosure is based on the appended
claims.
* * * * *